S390: Save and restore fprs/vrs while resolving symbols.

On s390, no fpr/vrs were saved while resolving a symbol
via _dl_runtime_resolve/_dl_runtime_profile.

According to the abi, the fpr-arguments are defined as call clobbered.
In leaf-functions, gcc 4.9 and newer can use fprs for saving/restoring gprs
instead of saving them to the stack.
If gcc do this in one of the resolver-functions, then the floating point
arguments of a library-function are invalid for the first library-function-call.
Thus, this patch saves/restores the fprs around the resolving code.

The same could occur for vector registers. Furthermore an ifunc-resolver
could also clobber the vector/floating point argument registers.
Thus this patch provides the further variants _dl_runtime_resolve_vx/
_dl_runtime_profile_vx, which are used if the kernel claims, that
we run on a machine with vector registers.

Furthermore, if _dl_runtime_profile calls _dl_call_pltexit,
the pointers to inregs-/outregs-structs were setup invalid.
Now they point to the correct location in the stack-frame.
Before branching back to the caller, the return values are now
restored instead of containing the return values of the
_dl_call_pltexit() call.
On s390-32, an endless loop occurs if _dl_call_pltexit() should be called.
Now, this code-path branches to this function instead of just after the
preceding basr-instruction.

ChangeLog:

	* sysdeps/s390/s390-32/dl-trampoline.S: Include dl-trampoline.h twice
	to create a non-vector/vector version for _dl_runtime_resolve and
	_dl_runtime_profile. Move implementation to ...
	* sysdeps/s390/s390-32/dl-trampoline.h: ... here.
	(_dl_runtime_resolve) Save and restore fpr/vrs.
	(_dl_runtime_profile) Save and restore vrs and fix some issues
	if _dl_call_pltexit is called.
	* sysdeps/s390/s390-32/dl-machine.h (elf_machine_runtime_setup):
	Choose the correct resolver function if running on a machine with vx.
	* sysdeps/s390/s390-64/dl-trampoline.S: Include dl-trampoline.h twice
	to create a non-vector/vector version for _dl_runtime_resolve and
	_dl_runtime_profile. Move implementation to ...
	* sysdeps/s390/s390-64/dl-trampoline.h: ... here.
	(_dl_runtime_resolve) Save and restore fpr/vrs.
	(_dl_runtime_profile) Save and restore vrs and fix some issues
	* sysdeps/s390/s390-64/dl-machine.h: (elf_machine_runtime_setup):
	Choose the correct resolver function if running on a machine with vx.

1 files changed, 211 insertions, 0 deletions

diff --git a/sysdeps/s390/s390-64/dl-trampoline.h b/sysdeps/s390/s390-64/dl-trampoline.h
new file mode 100644
index 0000000000..658e3a31c8
--- /dev/null
+++ b/sysdeps/s390/s390-64/dl-trampoline.h
@@ -0,0 +1,211 @@
+/* PLT trampolines.  s390x version.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* The PLT stubs will call _dl_runtime_resolve/_dl_runtime_profile
+ * with the following linkage:
+ *   r2 - r6 : parameter registers
+ *   f0, f2, f4, f6 : floating point parameter registers
+ *   v24, v26, v28, v30, v25, v27, v29, v31 : vector parameter registers
+ *   48(r15), 56(r15) : PLT arguments PLT1, PLT2
+ *   160(r15) : additional stack parameters
+ * The normal clobber rules for function calls apply:
+ *   r0 - r5 : call clobbered
+ *   r6 - r13 :	 call saved
+ *   r14 : return address (call clobbered)
+ *   r15 : stack pointer (call saved)
+ *   f0 - f7 : call clobbered
+ *   f8 - f15 : call saved
+ *   v0 - v7 : bytes 0-7 overlap with f0-f7: call clobbered
+               bytes 8-15: call clobbered
+ *   v8 - v15 : bytes 0-7 overlap with f8-f15: call saved
+                bytes 8-15: call clobbered
+ *   v16 - v31 : call clobbered
+ */
+
+	.globl _dl_runtime_resolve
+	.type _dl_runtime_resolve, @function
+	cfi_startproc
+	.align 16
+_dl_runtime_resolve:
+	stmg   %r2,%r5,64(%r15)	# save call-clobbered argument registers
+	cfi_offset (r2, -96)
+	cfi_offset (r3, -88)
+	cfi_offset (r4, -80)
+	cfi_offset (r5, -72)
+	std    %f0,104(%r15)
+	cfi_offset (f0, -56)
+	std    %f2,112(%r15)
+	cfi_offset (f2, -48)
+	std    %f4,120(%r15)
+	cfi_offset (f4, -40)
+	std    %f6,128(%r15)
+	cfi_offset (f6, -32)
+	stg    %r14,96(15)
+	cfi_offset (r14, -64)
+	lmg    %r2,%r3,48(%r15) # load args for fixup saved by PLT
+	lgr    %r0,%r15
+#ifdef RESTORE_VRS
+	aghi   %r15,-288        # create stack frame
+	cfi_adjust_cfa_offset (288)
+	.machine push
+	.machine "z13"
+	vstm   %v24,%v31,160(%r15)# store call-clobbered vector argument registers
+	cfi_offset (v24, -288)
+	cfi_offset (v25, -272)
+	cfi_offset (v26, -256)
+	cfi_offset (v27, -240)
+	cfi_offset (v28, -224)
+	cfi_offset (v29, -208)
+	cfi_offset (v30, -192)
+	cfi_offset (v31, -176)
+	.machine pop
+#else
+	aghi   %r15,-160        # create stack frame
+	cfi_adjust_cfa_offset (160)
+#endif
+	stg    %r0,0(%r15)      # write backchain
+	brasl  %r14,_dl_fixup	# call _dl_fixup
+	lgr    %r1,%r2		# function addr returned in r2
+#ifdef RESTORE_VRS
+	.machine push
+	.machine "z13"
+	vlm    %v24,%v31,160(%r15)# restore vector registers
+	.machine pop
+	aghi   %r15,288         # remove stack frame
+	cfi_adjust_cfa_offset (-288)
+#else
+	aghi   %r15,160         # remove stack frame
+	cfi_adjust_cfa_offset (-160)
+#endif
+	lg     %r14,96(%r15)	# restore registers
+	ld     %f0,104(%r15)
+	ld     %f2,112(%r15)
+	ld     %f4,120(%r15)
+	ld     %f6,128(%r15)
+	lmg    %r2,%r5,64(%r15)
+	br     %r1
+	cfi_endproc
+	.size _dl_runtime_resolve, .-_dl_runtime_resolve
+
+
+#ifndef PROF
+	.globl _dl_runtime_profile
+	.type _dl_runtime_profile, @function
+	cfi_startproc
+	.align 16
+_dl_runtime_profile:
+	stmg   %r2,%r6,64(%r15)		# save call-clobbered arg regs
+	cfi_offset (r2, -96)		# + r6 needed as arg for
+	cfi_offset (r3, -88)		#  _dl_profile_fixup
+	cfi_offset (r4, -80)
+	cfi_offset (r5, -72)
+	cfi_offset (r6, -64)
+	std    %f0,104(%r15)
+	cfi_offset (f0, -56)
+	std    %f2,112(%r15)
+	cfi_offset (f2, -48)
+	std    %f4,120(%r15)
+	cfi_offset (f4, -40)
+	std    %f6,128(%r15)
+	cfi_offset (f6, -32)
+	stg    %r12,24(%r15)		# r12 is used as backup of r15
+	cfi_offset (r12, -136)
+	stg    %r14,32(%r15)
+	cfi_offset (r14, -128)
+	lgr    %r12,%r15		# backup stack pointer
+	cfi_def_cfa_register (12)
+#ifdef RESTORE_VRS
+	aghi   %r15,-288		# create stack frame
+	.machine push
+	.machine "z13"
+	vstm   %v24,%v31,160(%r15)# store call-clobbered vector argument registers
+	cfi_offset (v24, -288)
+	cfi_offset (v25, -272)
+	cfi_offset (v26, -256)
+	cfi_offset (v27, -240)
+	cfi_offset (v28, -224)
+	cfi_offset (v29, -208)
+	cfi_offset (v30, -192)
+	cfi_offset (v31, -176)
+	.machine pop
+#else
+	aghi   %r15,-160		# create stack frame
+#endif
+	stg    %r12,0(%r15)		# save backchain
+	lmg    %r2,%r3,48(%r12)		# load arguments saved by PLT
+	lgr    %r4,%r14			# return address as third parameter
+	la     %r5,64(%r12)		# pointer to struct La_s390_64_regs
+	la     %r6,40(%r12)		# long int * framesize
+	brasl  %r14,_dl_profile_fixup	# call resolver
+	lgr    %r1,%r2			# function addr returned in r2
+	ld     %f0,104(%r12)		# restore call-clobbered arg fprs
+	ld     %f2,112(%r12)
+	ld     %f4,120(%r12)
+	ld     %f6,128(%r12)
+#ifdef RESTORE_VRS
+	.machine push
+	.machine "z13"
+	vlm    %v24,%v31,160(%r15)	# restore call-clobbered arg vrs
+	.machine pop
+#endif
+	lg     %r0,40(%r12)		# load framesize
+	ltgr   %r0,%r0
+	jnm    1f
+
+	lmg    %r2,%r6,64(%r12)		# framesize < 0 means no pltexit call
+					# so we can do a tail call without
+					# copying the arg overflow area
+	lgr    %r15,%r12		# remove stack frame
+	cfi_def_cfa_register (15)
+	lg     %r14,32(%r15)		# restore registers
+	lg     %r12,24(%r15)
+	br     %r1			# tail-call to resolved function
+
+	cfi_def_cfa_register (12)
+1:	jz     4f			# framesize == 0 ?
+	aghi   %r0,7			# align framesize to 8
+	nill   %r0,0xfff8
+	slgr   %r15,%r0			# make room for framesize bytes
+	stg    %r12,0(%r15)		# save backchain
+	la     %r2,160(%r15)
+	la     %r3,160(%r12)
+	srlg   %r0,%r0,3
+3:	mvc    0(8,%r2),0(%r3)		# copy additional parameters
+	la     %r2,8(%r2)		# depending on framesize
+	la     %r3,8(%r3)
+	brctg  %r0,3b
+4:	lmg    %r2,%r6,64(%r12)		# restore call-clobbered arg gprs
+	basr   %r14,%r1			# call resolved function
+	stg    %r2,136(%r12)		# store return values r2, f0
+	std    %f0,144(%r12)		# to struct La_s390_64_retval
+	lmg    %r2,%r3,48(%r12)		# load arguments saved by PLT
+	la     %r4,64(%r12)		# pointer to struct La_s390_64_regs
+	la     %r5,136(%r12)		# pointer to struct La_s390_64_retval
+	brasl  %r14,_dl_call_pltexit
+
+	lgr    %r15,%r12		# remove stack frame
+	cfi_def_cfa_register (15)
+	lg     %r14,32(%r15)		# restore registers
+	lg     %r12,24(%r15)
+	lg     %r2,136(%r15)		# restore return values
+	ld     %f0,144(%r15)
+	br     %r14			# Jump back to caller
+
+	cfi_endproc
+	.size _dl_runtime_profile, .-_dl_runtime_profile
+#endif